Sub-fertility affects 10% to 15% of couples in the western world. This sub-fertility can, in half of the cases, be ascribed to female causes, in 20%-26% to male causes, and in 25%-30% the cause is unknown (J. L. Evers, 2002, Lancet 360:151-159). Many couples turn to in vitro fertilization (IVF) or intra-cytoplasmatic sperm injection (ICSI) to fulfil their child-wish. The success rate of these techniques is around 25% per started cycle (A. Andersen et al., 2007, Hum. Reprod 22:1513-1525). It would be of great emotional and economical benefit if this success rate could be improved. In view of the personal and societal burden of assisted pregnancy treatments, it is desirable to identify couples with a very low chance for success and couples with a high chance for spontaneous pregnancy, especially in couples where the cause of infertility is unknown and show a high rate of spontaneous pregnancy where expectant management could be desirable for them (M. Brandes et al., 2011, Hum. Reprod 26:360-368). Thus, both for improving the treatments and for deciding in individual cases whether to proceed, there is a need for models that can accurately predict if a woman will become pregnant and give live birth after IVF/ICSI. For over a decade, models have been available that predict the chance of live birth on the basis of clinical data including age, number of previous failed IVF attempts and probable reason for infertility (W. Templeton et al., 1996, Lancet 348:1402-1406). For large groups, the ratio of predicted versus observed live birth was 40%-60% (S. M. Nelson and D. A. Lawlor, 2011, PLOS Medicine 8:1-10). These authors developed an improved model on the basis of data from over 140,000 women, using more stratification on age and cause of infertility, the procedure (to be) used, source of the egg and duration of the child-wish. When the area under the curve for the reporter-operated curve (AUROC) of the new model is used for how well this new model functions, a slight but significant increase was reported (from 0.6184 to 0.6335). This model seems to give a good prediction on larger groups of women (more than 10,000). However, it is not known yet how well this model predicts on an individual basis.
The route to a live birth can be reduced to three critical steps: fertilization of the egg, acceptance of the fertilized egg by the female environment, and further development up to actual live birth. When the first step is artificially taken care of (like in IVF and ICSI), the chance to reach a live birth can be described by markers for the second step. However, the factors that are responsible for acceptance of the fertilized egg are virtually unknown. It is thus currently impossible to establish criteria that would predict success in this second step.
Therefore, there is still need for a model that can more reliably predict the chance of a successful IVF/ICSI treatment on an individual basis.